//设置cookie
function setCookie(name,value)
{
    var Days = 3;
    var exp = new Date();
    // exp.setTime(exp.getTime() + Days*24*60*60*1000);
    exp.setTime(exp.getTime() + 30*60*1000);
    document.cookie = name + "="+ value + ";expires=" + exp.toGMTString() + ";path=/";
}

//获取cookie
function getCookie(name)
{
    var arr,reg=new RegExp("(^| )"+name+"=([^;]*)(;|$)");
    if(arr=document.cookie.match(reg)){
        return unescape(arr[2]);
    }else{
        return null;
    }
}

//删除cookie
function delCookie(name)
{
    var exp = new Date();
    exp.setTime(exp.getTime() - 1);
    var cval=getCookie(name);
    if(cval!=null){
        document.cookie= name + "="+cval+";expires="+exp.toGMTString() + ";path=/";
    }
}